1. Field of the Invention
The present invention relates to a sheet conveying apparatus having a conveyance guide, and to an image forming apparatus including the sheet conveying apparatus, e.g., a copying machine, a printer, a facsimile, or a multifunction peripheral of these apparatuses. More particularly, the present invention relates to cleaning of the conveyance guide which is equipped in the apparatus main body.
2. Description of the Related Art
A conventional electro-photographic image forming apparatus, such as a copying machine, a printer, a facsimile, or a multifunction peripheral of these apparatuses, includes a sheet conveying apparatus configured to convey a sheet, and an image forming unit configured to form a toner image on the sheet which has been conveyed by the sheet conveying apparatus. In general, the sheet conveying apparatus has a conveyance guide for guiding a sheet to be conveyed, and is configured to guide the sheet between the conveyance guides.
In recent years, a print on-demand (POD) market has required high productivity, increased function, and high durability for an image forming apparatus used in the POD market. Since the image forming apparatus deals with many media, the image forming apparatus may convey a sheet containing much paper dusts. Further, in such a highly durable image forming apparatus, a large number of sheets passes through the apparatus in one period of service maintenance. Therefore, in the image forming apparatus, the paper dusts coming from the sheets could accumulate on the conveyance guide in large quantity.
In such an image forming apparatus, since the paper dusts accumulates on the conveyance guide as use time increases, the accumulated paper dusts could generate conveyance faults of a sheet or image defects. Thus, in order to prevent these problems, the conveyance guide is configured to be a drawable conveyance unit, and an operator cleans the conveyance guide by drawing out the conveyance unit from an apparatus main body at a time of service maintenance.
Japanese Patent Application Laid-Open No. 2000-118760 discusses a technique by which a user can easily clean a part where paper dusts have a tendency to accumulate. In this technique, an apparatus main body includes a cleaning unit which is in contact with a conveyance guide serving as a sheet control member. By drawing out the conveyance guide in the direction intersecting the sheet conveyance direction, a user can clean paper dusts and dusts accumulating on the conveyance guide.
In recent years, positioning of an image leading edge and a sheet (leading edge registration) with higher accuracy has become necessary to improve an image quality. Thus, conveyance units on the upstream side of an image bearing member such as a photosensitive drum or an intermediate transfer belt, adopt following configuration in many cases. When a pair of upper and lower conveyance guides is configured to be drawn out to the outside as a unit, an attachment position deviates at a time of attaching and conveyance accuracy decreases. Thus, only a lower conveyance guide of the conveyance unit can be drawn out. In addition, according to this configuration of the conveyance unit, an operator can be prevented from accidentally touching and damaging the image bearing members such as a photosensitive drum and an intermediate transfer belt during a cleaning operation.
When only one of a pair of the conveyance guides is configured to be drawn out, an operator can easily draw out and clean the conveyance guide. However, an operator should put his or her hand into an apparatus main body and cleans the conveyance guide remaining in the apparatus main body. Thus, the operator can not fully clean the conveyance guide remaining in the apparatus main body. Therefore, an apparatus having good operability which can be more accurately cleaned is required.